Should I use paper or plastic bags at the grocery store?

Neither one is better. Best choice: bring your own cloth bag.

Should I dry my hands with paper towels or the electric blow dryer?

Use the dryer if you can’t drip dry.

Should I wash my dishes by hand or use the dishwasher?

If you and your dishwasher are efficient, by all means bypass the sink.

Is it better to leave [lights, cars, computers] on when I’m not using them, or turn them off and restart them?

Restart! Whether you’re driving, defeating darkness, or doing work, it takes more energy to keep your power-suckers running than it does to turn them off and on.

My old [car, refrigerator, washing machine] isn’t energy efficient. Is it worse to keep using it, or to toss it and buy a new one?

In general, it’s better to upgrade (whether washing machine, fridge, dishwasher, or car) — but make sure your old machine is reused or recycled if possible.

Should I use cotton or disposable diapers?

I know you worry, parents, but honestly, it’s a wash. Here’s an idea: go diaperless!

Is it better to buy organic food from far away, or non-organic food grown locally?

Ideally, buy food that is both organic and local — but if you have to choose, local is the way to go.

I want to follow your recommendation and buy compact fluorescent lightbulbs, but I’ve discovered they contain mercury. What should I do?

Buy them anyway — the small amount of mercury (less than in a watch battery) can be handled by a hazardous-waste facility.

Which plastics are OK?

We don’t like plastic, in general. But just make sure you avoid #3.

Which is better: Diesel? Biodiesel? Straight vegetable oil? Hybrid?

They’re all bad. Stop driving!

But while you work toward that goal, here are thoughts on some of your quandaries: diesel vs. regular gasoline; converting to biodiesel; converting to veggie oil; biodiesel vs. veggie oil; and hybrids vs. veggie oil.

Can I put my [milk carton, stapled paper, nose wipe tissues, number 17 bottle] in the recycling?

I don’t know. The only people who know are those running your recycling program — usually your municipality. Those same people should be able to answer questions about why certain objects are accepted and others are not.

What’s the one thing I can do to help the environment?

Watch out, helping the environment becomes addictive. There’s no one answer, but try to limit your consumption and keep the big picture in mind.